Cables, such as telecommunication cables, may carry hundreds and sometimes thousands of pairs of insulated wires, enclosed within flexible shields or tubular sheaths. When two or more cable ends are joined together, as for example when extending a cable or when tapping into an extended cable, a splice or splice area is created. The splice area should be enclosed for protection from the environment. For example, if the closure is an aerial closure, used with aerially suspended cables, protection against damaging interference from weather elements, animals, plants and so forth necessary.
Structures or arrangements for enclosing such portions of cables are frequently referred to as "splice closures". Such closures are typically adapted to enclose therein at least two, and sometimes more, "cable ends." The term "cable end", and variants thereof as used herein, refers to an area of exposure of insulated conductors, i.e., wires and any additional wrappings or coverings involved.
Splice closures generally comprise an elongate, typically cylindrical, outer casing having first and second opposite ends. Cables to be joined at the splice area(s) are generally directed into the casing through the casing ends. At each of the casing ends, seal means are provided in order to ensure an environmental seal around the cables, i.e. between the cables and the interior of the cable closure.
One type of closure, of particular importance, is generally referred to as the "aerial closure". An aerial closure is adapted to be used when suspended in the air, typically from a support cable or the like. Through the use of such a closure, a cable splice for suspended cables is accommodated. Typically, means are provided to ensure a conductive, and therefore grounding, contact between the cable sheaths of cables spliced in the closure.
There are a number of problems and features which it is generally desirable that a cable enclosure address. The major ones of these relate to, and concern, the following:
A sealing arrangement with cables extending into the cable closure must be provided. In some arrangements this may be provided by means of structural members permanently mounted on the enclosure. In others, separable end caps or washers may be utilized in association with the closure. When this latter type of arrangement is used, it is necessary and desirable for the closure to include means facilitating mounting and positioning of the end caps or washers therein.
The closure should be readily mountable around an aerial cable splice, or the like. This is facilitated by appropriate hanger means for association with the support cable, and also appropriate means for permitting the enclosure to be selectively opened or closed, around an associated cable splice and end cap arrangements that fit over existing cables.
Preferably, a multi-piece system is avoided. Conventional multi-piece systems can be difficult to assemble, especially by workers supported by a ladder, bucket system or the like. The problems are exacerbated if the worker is operating under adverse conditions, such as in high winds or otherwise inclement weather.
Occasionally it may be necessary to gain access to an enclosed cable splice area. It is preferred that a cable splice closure be readily manipulatable to provide access to the interior thereof, and any enclosed cable splice arrangement. Preferably, the arrangement is such as to generally inhibit unintended or inadvertent opening. However, preferably a quick opening system is provided, for convenience. Most preferably, the arrangement is such that opening can be accomplished without removal of the arrangement from an associated support cable.
Also, once the closure is opened it may be necessary for a worker to manipulate elements inside. Preferably, the arrangement is organized such that when opened, many portions of the cable splice(s) are in view, and are readily accessible for maintenance.
Cable splices may be of a variety of types, and include fairly simple two-cable arrangements as well as very complex multi-cable arrangements. Some arrangements may be very large in transverse or longitudinal extension, whereas others may be very small. It would be preferred that a cable enclosure arrangement be selectively adjustable or extendable in length, to accommodate cable splices requiring greater volume.
A cable enclosure should provide a good protective shield to the environment. Preferably means are provided to limit water leakage, for example from rain, to an interior thereof. Also, preferably means are provided for drainage of water from an interior of the cable enclosure, should any leakage occur.
It is also preferred that cable closures include means insulating the cable splice from sudden changes in temperature. Preferably this is accomplished at a relatively low cost, and without a substantial increase in complexity of manufacture.
It is also preferred that the closure system be readily manufactured in a relatively inexpensive manner, and by mass manufacturing techniques.
A wide variety of cable closure systems have been developed, some of which include features directed to at least some of the above related concerns. In general, however, no conventional, substantially universal, closure has been developed which readily and satisfactorily can meet all of the above concerns or meet certain selected ones in convenient manners. Such a closure has, however, been needed, since many closures are used in industries such as the telecommunications industry.